Highly frequent errors when playing Hypixel

Recently, I have been playing Minecraft on Hypixel a lot. (I was doing skyblock, but that’s not the point.)
However, a lot of times, when moving between servers, I get 1 of 2 possible errors:

1. An established connecting was forcibly terminated by the remote host.
2. An established connection was forcibly terminated by the software in your host machine.

I have optifine for performance, disabling it didn’t help. I run 1.12 minecraft.